Mite composition, use thereof, method for rearing a phytoseiid predatory mite, rearing system for rearing said phytoseiid predatory mite and methods for biological pest control on a crop

ABSTRACT

The present invention relates to a novel mite composition comprising a population of a phytoseiid predatory mite species and a factitious host population, which may be employed for rearing said phytoseiid predatory mite species or for releasing the pyrltoseiid predatory mite species in a crop. According to further aspects the invention relates to a method for rearing a phytoseiid predatory mite species, to the use of the mite composition and to a method for biological pest control in a crop, which employ the mite composition.

This invention according to a first aspect relates to a novel mitecomposition.

According to a second aspect the invention relates to a novel method forrearing a phytoseiid predatory mite species.

According to a third aspect the invention relates to a novel use of theAstigmatid mite species Carpoglyphus lactis as a factitious host, forrearing a phytoseiid predatory mite species.

According to a fourth and fifth aspect the invention relates to a novelrearing system for rearing a phytoseiid predatory mite species and tothe use of this rearing system for the control of crop pests.

According to yet further aspects the invention relates to a method forbiological pest control in a crop employing the mite compositionaccording to the invention.

In the following description and claims the names of the phytoseiidmites is as referred to in de Moraes, G. J. et al., 2004, unlessotherwise stated. An overview of the referenced families and species isprovided in FIG. 1.

Phytoseiid predatory mites (Phytoseiidae) are widely used for biologicalcontrol of spider mites and thrips in greenhouse crops. The mostimportant thrips species in greenhouse crops are Western Flower Thrips(Frankliniella occidentalis) and Onion Thrips (Thrips tabaci). They canbe controlled with the predatory mites Amnblyseius cucumeris andAmblyseius barkeri (Hansen, L. S. and Geyti, J., 1985; Ramakers, P. M.J. and van Lieburg, M. J., 1982; Ramakers, P. M. J., 1989; Sampson, C.,1998; and Jacobson, R. J., 1995) and Iphiseius degenerans (Ramakers, P.M. J. and Voet, S. J. P., 1996). In the absence of prey these speciesare able to establish and maintain in crops which provide a continuoussupply of pollen, such as sweet peppers (Capsicum annuum L.). In cropswhere pollen is not freely available, such as for example cucumbers andmost ornamental crops, these species cannot be used unless food isartificially provided. This can be done by dusting plant pollen on thecrop.

Alternatively a controlled release rearing system (as disclosed bySampson, C. (1998) or in GB2393890) can be used for Amblyseiuscucumeris. This controlled release rearing system consists of a sachetwith a compartment which contains a food mixture, consisting of bran,yeast and wheat germ; a population of the grain mite Tyrophagusputrescentiae and a population of the predatory mite Amblyseiuscucumeris. The grain mite Tyrophagus putrescentiae will develop anactive population on the food mixture and serves as a factitious hostfor the predatory mite population. The sachets are hung in the crop bymeans of a hook and will continuously release predatory mites over aperiod of 4 to 6 weeks.

Because Amblyseius cucumeris has a rather weak numerical response to thepresence of food, large quantities of predatory mites have to bereleased into a crop in order to have sufficient pest control. This iseconomically possible because Amblyseius cucumeris can be economicallyreared in very large quantities on the grain mite Tyrophagusputrescentiae, which may be reared in sufficient amounts on the abovedescribed food mixture.

Although there are much more efficient predatory mites for thripscontrol with a higher predation rate and numerical response, such asTyphlodromalus limonicus and Iphiseius degenerans, Amblyseius cucumerisis still the most commonly used species because it can easily be rearedin very large quantities.

Iphiseius degenerans is mass-reared on Castor Bean Plants (Ricinuscommunis L., Euphorbiaceae) which provide a continuous supply of pollenon which the mites can develop large populations. Because of the largesurface and high investment in greenhouses needed for growing theplants, the cost price of Iphiseius degerenans is very high compared toAmblyseius cucumeris. Due to this high cost price growers can onlyrelease very low numbers, typically 1000-2000 predatory mites perhectare. Therefore, the application of Iphiseius degenerans is limitedto peppers (Capsicum annuum L.), which provide sufficient pollen onwhich the predatory mites can develop a population, which is sufficientfor pest control. It may take several months before the population ofIphiseius degenerans is at full strength in a crop in order to be ableto have a significant impact on thrips pest populations.

Two-spotted Spider Mites (Tetranychus urticae) are successfullycontrolled in greenhouse and outdoor crops world-wide by releasingpredatory mites. The most important species are Phytoseiulus persimilis(Hussey., N. W. and Scopes, N. E. A., 1985), which is the oldest mitewhich is commercially available for biological control and Neoseiuluscalifornicus (Wei-Lan Ma and Laing, J. E., 1973). Both predatory mitesare mass-reared on their natural host Tetranychus urticae on bean plants(Phaseolus vulgaris) in greenhouses. Castagnoli, M. and Simoni, S.(1999) have also described a method for mass-rearing Neoseiuluscalifornicus on the House Dust Mite Dermatophagoides farinae. However,house Dust Mites (Dermatophagoides farinae and Derinatophagoidespteronyssinus) produce important allergens, implicated in allergicasthma, rhinitis, conjunctivitis and dermatitis. Therefore their use incontrolled release rearing systems for releasing predatory mites incrops has disadvantages. Another disadvantage is that when House DustMites are used for mass-rearing purposes, extensive measures areadvisable and in certain cases necessary for worker protection.

Scientific literature reports several predatory mites which prey onwhiteflies (Teich, Y. 1966; Swirski, E. et al., 1967; Nomikou, M. etal., 2001). Unfortunately, to date there are still no predatory mitescommercially available for biological control of whiteflies. Probablybecause despite the known predation of predatory mites on whitefliestheir usability as augmentative biological control agents againstwhiteflies has not been recognized in the art. In augmentativebiological control, biological agents are released in a crop for thecontrol of a pest. Even more important, no economic mass-rearingsystems, necessary for allowing the release of large numbers of thepredatory mites into a crop, which is of utmost importance for theirusability as an augmentative biological control agent, are available inthe art for those predatory mite species which could potentially beefficacious against white flies.

Instead whiteflies are controlled by releasing parasitoid wasps such asEncarsia formosa and Eretmocerus eremicus against the GreenhouseWhitefly Trialeurodes vaporariorum and the parasitoid wasp Eretmocerusmundus against the Tobacco Whitefly Bemisia tabaci. Also severalpredators are mass-reared and released, such as for example thepredatory Mirid bug Macrolophus caliginosus and the coccinellidDelphastus catalinae. Mass-rearing of all these parasitoids andpredators involves the greenhouse production of plants and whiteflieswhich involves considerable investments.

Biological control of whiteflies and other crop pests with predatorymites which can be economically reared in large quantities on afactitious host mite in a rearing medium would be very advantageousbecause such a rearing system uses a limited surface. Furthermore insuch a system rearing of the predatory mite can be performed incontrolled climate rooms. As such it does not require large investmentsin greenhouses and crops.

Recent research has indicated the potential of the predatory miteAmblyseius swirskii as a very efficient biological control agent ofthrips (Thrips tabaci and Frankliniella occidentalis) and whiteflies(Trialeurodes vaporariorum and Bemisia tabaci) (Nomikou, M., Janssen,A., Schraag, R. and Sabelis, M. W., 2001; Messelink, G. & Steenpaal, S.2003; Messelink, G. 2004; Messelink, G. & Steenpaal, S. 2004; Bolckmans,K. & Moerman, M. 2004; Messelink, G. & Pijnakker, J. 2004). Amblyseiusswirskii has shown a very strong numerical response to the presence ofpests and plant pollen. This means that, compared to Amblyseiuscucumeris, much lower numbers of mites have to be released in order toacquire good biological control. In one trial, release of 1 Amblyseiusswirskii per leaf on sweet pepper plants resulted in the same level ofcontrol of Western Flower Thrips as releasing 30 Amblyseius cucumerisper leaf (Bolckmans, K. & Moerman, M. 2004).

The prior art describes rearing of Amblyseius cucumeris and Amblyseiusbarkeri with the aid of a factitious host mite species from the genusTyrophagus, in particular Tyrophagus putrescentiae, Tyrophagus tropicus,Tyrophagus casei (Sampson, C., 1998; Jacobson, R. J., 1995; Bennison, J.A. and R. Jacobson, 1991; Karg et al., 1987; and GB293890) and from thegenus Acarus, in particular Acarus siro (Beglyarov et al., 1990) andAcarus farris (Hansen, L. S. and J. Geyti, 1985; Ramakers, P. M. J. andvan Lieburg, M. J., 1982), which all belong to the family of theAcaridea.

The most common rearing host for Amblyseius cucumeris is Tyrophagusputrescentiae. An important disadvantage of Tyrophagus putrescentiae isthat it can cause plant damage to young plant leaves when it is presenton crops, e.g. when used as a factitious host in slow release breedingsachets similar to that disclosed by (Sampson, C., 1998) or in GB293890.This is especially the case in cucumber crops during periods of highhumidity especially if this is combined with a low light intensity.

Castagnoli et al. have also described the possibility of mass-rearing.Neoseiulus californicus (Castagnoli, M. and S. Simoni, 1999) andAmblyseius cucumeris (Castagnoli, M., 1989) on the House Dust MiteDermatophagoides farinae as a factitious rearing host. However, HouseDust Mites (Dermatophagoides farinae and Dermatophagoides pteronyssinus)produce important allergens, implicated in allergic asthma, rhinitis,conjunctivitis and dermatitis.

Thus there is a need in the art for additional factitious hosts whichcan be used for mass rearing beneficial mites, such as predatory mites.Especially for rearing of Amblyseius swirskii. For this predatory miterearing has only been disclosed in the art using pollen (Messelink, G. &Pijnakker, J. 2004) or eggs from the lepidopterans Corcyra cephalonicaor Ephestia kuehniella (Romeih, A. H. M. et al., 2004).

Rearing on pollen necessitates either large greenhouse areas for theproduction of plants such as Castor Bean Plants (Ricinus communis) toobtain sufficient pollen, or collecting suitable plant pollen such asfrom Cattail (Typha spp.) outdoors. Collecting plant pollen outdoors isvery labour intensive and only limited quantities can be collected.Honeybee collected plant pollen is unsuitable for rearing predatorymites.

Rearing on lepidopteran eggs requires large investments in productionfacilities and thus is very expensive.

In view of the above there is a need in the art for alternativefactitious host mites, which can be employed in the mass-rearing ofphytoseiid predatory mites.

It has now been found that Astigmatid mite species from the family ofthe Carpoglyphydae may be used as factitious host for a great number ofphytoseiid predatory mite species.

Thus according to a first aspect the invention relates to a mitecomposition comprising a rearing population of a phytoseiid predatorymite species and a factitious host population comprising at least onespecies selected from the family of the Carpoglyphidae such as from thegenus Carpoglyphus, preferably the Dried Fruit Mite Carpoglyphus lactis(Linne, 1758) (Acari: Carpoglyphidae).

The phytoseiid predatory mite species which are most likely to be ableto feed on Carpoglyphidae and in particular Carpoglyphus lactis areoligophagous phytoseiid predatory mite species. An oligophagousphytoseiid predatory mite species is a phytoseiid predatory mite specieswhich is able to use at least a few different prey species as a foodsource for its development (growth and reproduction). As such the termoligophagous predatory mite species in this specification includes apolyphagous mite species, being a predatory mite which can use a greatnumber of prey species as a food source for its development. Thus theterm oligophagous predatory mite species is to be understood to mean anon-monophagous predatory mite species.

A factitious host species is a species which inhabits a differentnatural habitat then the phytoseiid predatory mite, but nevertheless oneor more life stages of the factitious host are suitable prey for atleast one life stage of the phytoseiid predatory mite. Most importantlythe phytoseiid predatory mite has the ability to develop and toreproduce when feeding upon a diet of the factitious host such that thenumber of individuals in the rearing population can grow.

Phytoseiid predatory mites have their natural habitat on plants wherethey prey on pest organisms (insects and mites). They may be isolatedfrom their natural habitats as described by de Moraes et al., 2004.

Carpoglyphidae are described by Hughes, A. M. (1977). Based on thedisclosure of this document the skilled person will be able to isolatespecific species from this family from their natural habitat.Carpoglyphus lactis is a cosmopolitan species which develops on and in avariety of stored organic materials. It is mainly found on dried fruit,such as dried figs, prunes, raisins, etcetera and on the debris inhoneybee hives (Hughes, A. M. 1977; Chmielewski; W., 1971 (a);Chmielewski, W., 1971 (b)).

Thus the composition according to the invention provides a newassociation of mites, which does not occur naturally, as the phytoseiidpredatory mite inhabits a different habitat then the Carpoglyphidae.

The composition according to the invention is not only suitable formass-rearing of a phytoseiid predatory mite. As it also comprises mobilepreying life stages of a phytoseiid predatory mite, or life stages whichcan develop into these mobile life stages, it can also be employed as abiological crop protection agent.

In a preferred embodiment the composition comprises a carrier for theindividuals of the populations. The carrier can be any solid materialwhich is suitable to provide a carrier surface to the individuals.Preferably the carrier provides a porous medium, which allows exchangesof metabolic gases and heat produced by the mite populations. Examplesof suitable carriers are plant materials such as (wheat) bran, buckwheathusks, rice husks, saw dust, corn cob grits etcetera.

It is further preferred if a food substance suitable for the factitioushost population is added to the composition. Alternatively the carrieritself may comprise a suitable food substance. A suitable food substancemay be similar to that described by Parkinson, C. L., 1992; Solomon, M.E. & Cunnington, A. M., 1963; Chmielewski, W, 1971 a; Chmielewski, W,1971 b or GB2393890.

According to a preferred embodiment of the composition the phytoseiidpredatory mite is selected from:

-   -   the subfamily of the Amblyseiinae, such as from the Genus        Amblyseius, e.g. Amblyseius andersoni, Amblyseius swirskii or        Amblyseius largoensis, from the genus Euseius e.g. Euseius        finlandicus, Euseius hibisci, Euseius ovalis, Euseius        victoriensis, Euseius stipulatus, Euseius scutalis, Euseius        tularensis, Euseius addoensis or Euseius citri, from the genus        Neoseiulus e.g. Neoseiulus barkeri, Neoseiulus californicus,        Neoseiulus cucumeris, Neoseiulus longispinosus, Neoseiulus        womersleyi, Neoseiulus idaeus or Neoseiulus fallacies, from the        genus Typhlodromalus e.g. Typhlodromalus limonicus or        Typhlodromalus peregrinus from the genus Typhlodromips e.g.        Typhlodromips montdorensis;    -   the subfamily of the Typhlodrominae, such as from the genus        Galendroinus e.g. Galendroinus occidentalis, from the genus        Typhlodromus e.g. Typhlodromus pyri, Typhlodromus doreenae or        Typhlodromus athiasae. These phytoseiid predatory mite species        may be considered as being oligophagous predatory mite species.

The phytoseiid predatory mite preferably is selected as Amblyseiusswirskii Athias-Henriot, 1962, (Chant and McMurtry), 2004,(=Typhlodromips swirskii (Athias-Henriot), 1962, De Moraes et al.,2004). For this species rearing on a factitious host mite has not beendisclosed in the art. The present invention now for the first timediscloses a mite composition which can be used for economic rearing ofAmblyseius swirskii by using a species from the family of theCarpoglyphidae as a factitious host. Making it possible to useAmblyseius swirskii as an augmentative biological pest control agent. Itshould however be understood that in certain embodiments of theinvention the phytoseiid predatory mite species is selected from aspecies other then Amblyseius swirskii.

Differences in acceptance of the factitious host may be observed betweendifferent strains of the phytoseiid predatory mite species. Furthermore,it might be possible to breed a strain which is adapted to a specificfactitious host by selective breeding.

In this specification the term rearing must be understood to include thepropagation and increase of a population by means of sexualreproduction.

A rearing population may comprise sexually mature adults from bothsexes, and/or individuals of both sexes of other life stages, e.g. eggsand/or nymphs, which can mature to sexually mature adults. Alternativethe rearing population may comprise one or more fertilized females. Inessence the rearing population is capable of increasing the number ofits individuals by means of sexual reproduction.

Preferably the factitious host population is a rearing population, asdefined above, such that it may sustain or even develop itself to acertain degree. If the factitious host is provided as a rearingpopulation, preferably a food substance for the factitious host is alsoprovided. The food substance may be similar to a food substance asdisclosed in Solomon, M. E. and Cunnington, A. M., 1963; Parkinson, C.L., 1992; Ramakers, P. M. J. and van Lieburg, M. J., 1982; GB2393890.

The factitious host is preferably selected as Carpoglyphus lactis.Carpoglyphus lactis also called the dried fruit mite is a cosmopolitanspecies which develops on and in a variety of stored organic materials.It is mainly found on dried fruit, such as dried figs, prunes, raisins,etcetera and on the debris in honeybee hives (Hughes, A. M., 1977;Chmielewski, W., 1971 (a); Chmielewski, W., 1971 (b)). Contrary toTyrophagus putrescentiae, Carpoglyphus lactis does not cause damage tocrops. Therefore, a factitious host from this preferred selection willhave benefits when the composition according to the invention is usedfor crop protection in such a way that individuals of the factitioushost population may come in contact with the crop e.g. when applieddirectly on or in the vicinity of the crop or when used inslow/controlled/sustained release sachets.

A further benefit of Carpoglyphus lactis is that it is considered to bea cosmopolitan species. As such international trade of productscomprising it will encounter less regulatory restrictions as isencountered in many countries for foreign species.

Also it has been found that Carpoglyphus lactis is in particular asuitable factitious host for Amblyseius swirskii as this predator canfeed on multiple life stages and under certain circumstances all lifestages of this host.

In the composition the number of individuals of the phytoseiid predatorymite species relative to the number of individuals of the factitioushost may be from about 1000:1 to 1:20, such as about 100:1 to 1:20 e.g.1:1 to 1:10, preferably about 1:4, 1:5 or 1:7.

The relative numbers may depend on the specific intended use of thecomposition and/or the stage of development of phytoseiid mitepopulation on the factitious host. In general compositions whereinindividuals of the factitious host are present in excess to theindividuals of the phytoseiid mite are preferred for rearing of thephytoseiid mite species, so that sufficient prey is provided to thephytoseiid mite. However, as the phytoseiid mite population willincrease while preying on the factitious host, the relative number ofindividuals of the phytoseiid mite species will increase.

A composition comprising a high relative numbers of the phytoseiidpredatory mite may be formed from a composition comprising a smallerrelative number and allowing the rearing population of the phytoseiidpredatory mite to develop by preying on the factitious host.Alternatively a composition comprising a small relative number of thephytoseiid predatory mite can be formed by mixing a compositioncomprising a higher relative number with a composition comprising asmaller relative number, including a composition comprising solely thefactitious host, optionally in combination with the carrier and/or afood substance suitable for the factitious host.

According to a further aspect the present invention relates to a methodfor rearing the phytoseiid predatory mite species. The method comprisesproviding a composition according to the invention and allowingindividuals of said phytoseiid predatory mite to prey on individuals ofsaid factitious host population.

For an optimal development of the phytoseiid predatory mite, thecomposition is e.g. maintained at 18-35° C., preferably 20-30° C., morepreferably 20-25° C., most preferably 22-25° C. Suitable relativehumidity ranges are between 75-95%, preferably 80-90%. These temperatureand relative humidity intervals are in general also suitable to maintainthe factitious host species.

It is preferred that the composition comprises a carrier which canprovide a porous medium and a food substance for the factitious hostspecie and that the factitious host species is maintained as a threedimensional culture on the carrier. In such a three dimensional culturemembers of the factitious host species are free to move in threedimensions. In this way they may infest a larger volume of the carrierand utilise the food substance more optimally. Considering the size ofthe mobile stages of the phytoseiid predatory mite species relative toindividuals of the factitious host, this organism will in general alsoinfest the total volume of the carrier, when foraging for the factitioushost. Preferably the three dimensional culture is obtained by providingthe carrier in a three dimensional layer, i.e. a layer having threedimensions, of which two dimensions are larger then one dimension.Exemplary is a horizontal layer with a length and breadth in the orderof metres and a certain thickness in the order of centimetres. A threedimensional layer is preferred because it will allow sufficient exchangeof metabolic heat and gasses and will provide a larger production volumecompared to a two dimensional layer.

According to a further aspect the invention is aimed to the use of anAstigmatid mite selected from the family of the Carpoglyphidae such asfrom the genus Carpoglyphus, preferably the species Carpoglyphus lactis,as a factitious host for rearing a phytoseiid predatory mite.

The Astigmatid mite is preferably selected from the genus Carpoglyphusand most preferably is Carpoglyphus lactis, for reasons discussed above.

The phytoseiid predatory mite is preferably selected from:

-   -   the subfamily of the Amblyseiinae, such as from the Genus        Amblyseius, e.g. Amblyseius andersoni, Amblyseius swirskii or        Amblyseius largoensis, from the genus Euseius e.g. Euseius        finlandicus, Euseius hibisci, Euseius ovalis, Euseius        victoriensis, Euseius stipulatus, Euseius scutalis, Euseius        tularensis, Euseius addoensis or Euseius citri, from the genus        Neoseiulus e.g. Neoseiulus barkeri, Neoseiulus californicus,        Neoseiulus cucumeris, Neoseiulus longispinosus, Neoseiulus        womersleyi, Neoseiulus idaeus or Neoseiulus fallacies, from the        genus Typhlodromalus e.g. Typhlodromalus limonicus or        Typhlodromalus peregrinus from the genus Typhlodromips e.g.        Typhlodromips montdorensis;    -   the subfamily of the Typhlodrominae, such as from the genus        Galendromus e.g. Galendromus occidentalis, from the genus        Typhlodromus e.g. Typhlodromus pyri, Typhlodromus doreenae or        Typhlodromus athiasae.

According to a further aspect the invention relates to a rearing systemfor rearing the phytoseiid predatory mite.

The rearing system comprises a container holding the compositionaccording to the invention. The container may be of any type which issuitable for restraining individuals of both populations. The rearingsystem may comprise means which facilitate exchange of metabolic gasesand heat between it's interior and it's exterior such as ventilationholes. Such ventilation holes must not allow the escape of individualsof the populations from the container. This can be effected by coveringthe ventilation holes e.g. with a mesh.

The rearing system may be suitable for mass-rearing the phytoseiid mitespecies. Alternatively the rearing system may also be used for releasingthe phytoseiid predatory mite in a crop. In this case it is preferredthat the container can be rendered suitable to release mobile stages ofthe phytoseiid predatory mite at a certain moment. This can be effectedby providing a closed opening in the container which can be opened.Alternatively or in combination therewith a relatively small releasingopening may be provided in the container, such that the number ofphytoseiid mobile stages which leave the container in a given timeinterval is restricted. In this way the rearing system may functionsimilar to the slow release or sustained release system as disclosed bySampson, C., 1998 and in GB2393890.

In such a rearing system for releasing the phytoseiid predatory mite ina crop the container is preferably dimensioned such that it can be hungin the crop or placed at the basis of the crop. For hanging in the cropthe container may be provided with hanging means, such as a cord or ahook.

According to a further aspect the invention is aimed at the use of thecomposition or the rearing system for controlling crop pests in acommercial crop.

The pest may be selected from, white flies, such as Trialeurodesvaporariorum or Bemisia tabaci; thrips, such as Thrips tabaci orFrankliniella spp., such as Frankliniella Occidentalis, spider mitessuch as Tetranychus urticae, tarsonemid mites such asPolyphagotarsonemus latus. The phytoseiid predatory mite Amblyseiusswirskii has shown a good efficacy for controlling these pests

The crop may be selected from, but is not restricted to (greenhouse)vegetable crops such as peppers (Capsicum annum, eggplants (Solanummelongena), Curcubits (Cucurbitaceae) such as cucumbers (Cucumissativa), melons (Cucumis melo), watermelons (Citrullus lanatus); softfruit (such as strawberries (Fragaria x ananassa), raspberries (Rubusideaus)), (greenhouse) ornamental crops (such as roses, gerberas,chrysanthemums) or tree crops such as Citrus spp.

The invention further relates to a method for biological pest control ina crop comprising providing a composition according to the invention tosaid crop.

The pest may be selected similarly as in the use according to theinvention.

In the method according to the invention the composition may be providedby applying an amount of said composition in the vicinity, such as on orat the basis of a number of crop plants. The composition may be providedto the crop plant simply by spreading it on the crop plant or at thebasis of the crop plant as is common practice for employing predatorymite compositions for augmentative biological pest control. The amountof the composition which may be provided to each individual crop plantby way of spreading may range from 1-20 ml such as 1-10 ml, preferably2-5 ml.

Alternatively the composition may be provided to the number of cropplants in the rearing system according to the invention which issuitable for releasing the phytoseiid predatory mite in a crop. Therearing system may be placed in the vicinity, such as in or at thebasis, of a number of crop plants.

In the method for biological pest control according to the invention itmay not be necessary to provide the composition to all crop plants. Ascommercial crops are normally densely cultivated. The phytoseiidpredatory mites may spread from one crop plant to another. The number ofcrop plants which must be provided with the composition according to theinvention in order to provide sufficient crop protection may depend onthe specific circumstances and can be easily determined by the skilledperson based on his experience in the field. Usually the number ofphytoseiid predatory mites released per hectare is more determining.This number may range from 1000-4 million per hectare, typically100.000-1 million or 50.000-500.000 per hectare.

In a further preferred embodiment of the method for biological pestcontrol according to the invention the crop is selected as described inrelation to the use of the composition.

The invention will now be further described with reference to thefollowing examples, which show non-limiting embodiments of differentaspects of the invention.

EXAMPLE 1

Mass-rearing of the Astigmatid Mite Carpoglyphus lactis.

Carpoglyphus lactis was mass-reared on a medium containing baker's yeast(Chmielewski, W., 1971 (a); Chmielewski, W., 1971 (b)).

The culture is kept in ventilated containers (for example buckets withsufficient ventilation holes with 47 micron gauze to prevent the mitesfrom escaping) at between 22° and 25° C. and a relative humidity of 85to 90%. Successful mass-rearing may be effected by adding fresh mediumat least once every week. The amount depends on the number of mites inthe medium but typically between 100 to 300% of medium of the originalvolume of the culture is added. The thickness of the rearing layer canbe 1 to 10 cm, but not too thick to ensure optimal exchange of metabolicgases such as carbon dioxide and oxygen and metabolic heat. Biomassweight percentages of mites to medium between 20% and 30% were reachedwhen Carpoglyphus lactis was reared on this medium. Typically thepopulation will increase 2 to 4 times each week.

EXAMPLE 2

Mass Rearing of Amblyseius swirskii on Carpoglyphus lactis

Amblyseius swirskii is reared in ventilated containers (for examplebuckets with sufficient ventilation holes to ensure optimal exchange ofmetabolic gases and heat with 47 micron gauze to prevent the mites fromescaping) with a layer of 5 to 25 cm of buckwheat husks as a carrier.

The carrier layer should not be too thick to ensure optimal exchange ofmetabolic gases such carbon dioxide and oxygen and metabolic heat. Atleast once every week a rearing population of Carpoglyphus lactis with abiomass weight percentages of mites to medium of 15% to 30% is added tothe container.

The quantity of Carpoglyphus lactis to be added is calculated based onthe number of the phytoseiid predatory mites and Carpoglyphus lactispresent in the rearing container. Optimally after adding freshCarpoglyphus lactis the ratio of predators to prey should be between 1:7to 1:12. The culture is kept at a temperature between 22° and 25° C., arelative humidity of 85 to 90% and a CO2 level of maximum 750 ppm in therearing container. In this way a rearing population of Amblyseiusswirskii can double to triple each week. Typically densities of 100 to500 predatory mites per gram of rearing substrate can be achieved.

EXAMPLE 3

Oviposition Test of Amblyseius swirskii on Juvenile and Adult LifeStages of Carpoglyphus lactis.

The objective of this experiment is to investigate if Amblyseiusswirskii has a preference for juvenile stages (eggs, larvae and nymphs)of Carpoglyphus lactis or that it can also feed on adult life stages ofthis factitious host. For this different rearing systems of Amblyseiusswirskii (some of them fed with juvenile stages of Carpoglyphus lactisand others fed with adults of Carpoglyphus lactis) were created. Thedifferences between the mean number of eggs laid per Amblyseius swirskiifemale per day in the case that the food source are adult stages ofCarpoglyphus lactis is compared to the case wherein the food source arejuvenile stages of Carpoglyphus lactis.

Material and Methods

At the beginning of the experiment the Amblyseius swirskii adults weretaken from an Amblyseius swirskii mass-culture which was started a fewweeks earlier. 30 young adult females and 12 males were picked up fromthis mass-culture and transferred to six freshly prepared rearingcontainers. 5 females and 2 males of Amblyseius swirskii were placed ineach one. In three of them as a food source was placed an ample amountof juvenile stages of Carpoglyphus lactis. The remaining three testcultures were fed with adults of Carpoglyphus lactis.

Once the six test cultures were prepared, they were located in a climateroom under controlled temperature (25° C.) and humidity (75%)conditions. After two or three days in these conditions, they were takenout. Six new rearing containers, similar to the previous ones, wereprepared to transfer the same 5 females and 2 males previously used.Ample amount of juvenile or adult stages of Carpoglyphus lactis as afood source were added to each test container as in the previous step.After transferring the males and females, the number of eggs was countedin the rearing containers from which they were transferred.

The old rearing systems were conserved in the climate room during two orthree days for a second counting in order to detect some possible hiddenoffspring, after which they were destroyed. Similar to the old rearingsystems, the new ones were also maintained to repeat the same procedure.Every day the residual amount of Carpoglyphus lactis in each rearingcontainer was checked. If necessary a sufficient amount was added.

Every two or three days data were obtained by evaluating the number ofoffsprings of both the new rearing (first counting) and the old one(second counting). Based on the number of females and on the totalamount of offspring which was found on each rearing container, the meannumber of eggs laid per female per day was obtained.

Results

Adult Stages of Carpoglyphus lactis as a Food Source

When comparing the evolution of the number of eggs laid per femaleduring the total experiment (making one assessment each 2-3 days), themean ranges from 1.27 to 2.07 eggs/female/day.

For the whole period, the general mean is 1.80 eggs per female per day.The total amount of eggs laid per female is about 29 over a 16 daysperiod. Comparing the mean number of eggs laid per female per day forthe first, second and third independent rearing container, these are1.84, 1.72 and 1.85, respectively. The experimental data is presented intable 1 below.

TABLE 1 Food source: adults of Carpoglyphus lactis. Data of the meannumber of eggs laid per Amblyseius swirskii female per day for the 3independent rearing systems and for the global experiment. Mean Totalegg/day/ eggs/day/ Exp. Date Females offspring female female 1 10/11 515 1.50 1.84 15/11 5 24 1.60 17/11 5 17 1.70 19/11 5 23 2.30 22/11 5 302.00 24/11 5 17 1.70 26/11 5 21 2.10 2 10/11 5 10 1.00 1.72 15/11 5 312.07 17/11 5 20 2.00 19/11 5 21 2.10 22/11 5 31 2.07 24/11 5 13 1.3026/11 5 15 1.50 3 10/11 5 13 1.30 1.85 15/11 5 34 2.27 17/11 5 23 2.3019/11 5 18 1.80 22/11 5 25 1.67 24/11 5 19 2.38 26/11 5 10 1.25 Meaneggs/day/ eggs/day/ Day Period Females Offspring female female 10/11 0-2 days 15 38 1.27 1.80 15/11  3-5 days 15 89 1.98 17/11  6-7 days 1560 2.00 19/11  8-9 days 15 62 2.07 22/11 10-12 days 15 86 1.91 24/1113-14 days 14 49 1.75 26/11 15-16 days 14 46 1.64Juvenile Stages of Carpoglyphus lactis as a Food Source

If we compare the evolution of the number of eggs laid per female duringthe total experiment (making one assessment each 2-3 days), it was foundthat the mean ranges from 1.43 to 2.07 eggs/female/day.

For the whole period, the mean is 1.84 eggs per female per day. Thetotal amount of eggs laid per female is about 33 over a 18 days period.Comparing the mean number of eggs laid per female per day for the 3independent rearing containers, the means for the first, second andthird rearing systems are 1.72, 1.89 and 1.81, respectively. The resultsare shown in table 2 below.

TABLE 2 Food source: juvenile stages of Carpoglyphus lactis. Data of themean number of eggs laid per Amblyseius swirskii female per day for the3 independent rearing systems and for the global experiment. Mean Totalegg/day/ eggs/day/ Exp. Day Females offspring female female 1 10/11 5 181.80 172 12/11 5 21 2.10 15/11 5 31 2.07 17/11 5 17 1.70 19/11 5 16 1.6022/11 5 33 2.20 24/11 4 10 1.25 26/11 4  8 1.00 2 10/11 6 15 1.25 1.8912/11 6 24 2.00 15/11 6 31 1.72 17/11 6 25 2.08 19/11 6 26 2.17 22/11 636 2.00 24/11 6 25 2.08 26/11 6 22 1.83 3 10/11 5 20 2.00 1.81 12/11 521 2.10 15/11 5 26 1.73 17/11 5 21 2.10 19/11 4 17 1.70 22/11 4 24 2.0024/11 4 13 1.63 26/11 4 10 1.25 Mean eggs/day/ eggs/day/ Day PeriodFemales Offspring female female 10/11  0-2 days 16 53 1.66 1.84 12/11 3-4 days 16 66 2.06 15/11  5-7 days 16 88 1.83 17/11  8-9 days 16 631.97 19/11 10-12 days 15 59 1.97 22/11 13-14 days 15 93 2.07 24/11 15-16days 14 48 1.71 26/11 17-18 days 14 40 1.43The results show that Amblyseius swirskii can reproduce on both juvenileand adult stages of Carpoglyphus lactis.

EXAMPLE 4

Oviposition of Amblyseius cucumeris on Carpoglyphus lactis.

With the same general experimental outline as described in example 3,the mean number of eggs layed per Amblyseius cucumeris female when usingCarpoglyphus lactis as a food source was determined.

In this experiment however, no discriminatory determinations forjuvenile and adults of the factitious host were done. Insteadindividuals of the Carpoglyphus lactis population were addednon-selectively.

Results

If we compare the evolution of the number of eggs laid per female in thetotal experiment (making one assessment each 2-3 days), we appreciatethat, avoiding the first period (2 days) where the average is 1.72eggs/female/day, in the 5 next periods the mean ranges from 2.17 to 2.31eggs/female/day. For the whole period, the general mean is 2.13eggs/female/day. The data are presented in table 3 below.

TABLE 3 Data for the mean number of eggs laid per female per day for the3 independent rearing systems and for the global experiment. Mean Totalegg/day/ eggs/day/ Exp. Day Females offspring female female 1 29/10 5 191.90 2.32 01/11 5 37 2.47 05/11 5 26 2.60 08/11 5 35 2.33 10/11 5 242.40 12/11 5 22 2.20 2 29/10 5 25 2.50 2.39 01/11 5 37 2.47 05/11 5 252.50 08/11 5 36 2.40 10/11 5 19 1.90 12/11 5 26 2.60 3 29/10 6 11 0.922.13 01/11 6 31 1.72 05/11 6 23 1.92 08/11 6 33 1.83 10/11 5 22 2.2012/11 4 14 1.75 Mean eggs/day/ eggs/day/ Day Period Females Offspringfemale female 29/10  0-2 days 16 55 1.72 2.13 01/11  3-5 days 16 1052.19 05/11  6-7 days 16 74 2.31 08/11  8-10 days 16 104 2.17 10/11 11-12days 15 65 2.17 12/11 13-14 days 14 62 2.21The results show that Amblyseius cucumeris is able to reproduce onCarpoglyphus lactis.

REFERENCE

Athias-Henriot, C. (1962) Amblyseius swirskii, un nouveau phytoseiidevoisin d'A. andersoni (Acariens anactinotriches). Annales de l'EcoleNationale d'Agriculture d'Alger, Algeria, 3, 1-7.

Beglyarov et al., 1990, Flour mite for mass breeding of phytoseiids,Zashchita-Rastenii, no. 10, pp 25. Bennison, J. A. and Jacobson, R.,1991, Integrated control of Frankliniella occidentalis (Pergande) in UKcucumber crops—evaluation of a controlled release system of introducingAmblyseius cucumeris, Med. Fac. Landbouww. Rijksuniv. Gent, 56/2a, pp251-255.

Bolckmans, K. & Moerman, M. 2004, Nieuwe roofmijt verandert bestrijdingin paprika. Groenten & Fruit 41: 24-25

Castagnoli, M., 1989, Biologia e prospettive di allevamento massale diAmblyseius cucumeris (Oud.) (Acarina: Pyroglyphidae) com preda.

Castagnoli, M. and Simoni, S., 1999, Effect of long-term feeding historyon functional and numerical response of Neoseiulus californicus (Acari:Phytoseiidae), Experimental & Applied Acarology, 23, pp 217-234.

Castagnoli M., Simoni S. Biliotti N., 1999, Mass-rearing of Amblyseiuscalifornicus on two alternative food source—In: J. Bruin, L. P. S. vander Geest and M. W. Sabelis (eds), Ecology and Evolution of the Acari,Kluwer Acad, Publ., Dordrecht, The Nederlands, pp. 425-431.

Chant, D. A., and J. A., McMurtry, 2004, A review of the subfamilyAmblyseiinae Muma (Acari: Phytoseiidae): Part III. The tribe Amblyseiiniwainstein, subtribe Amblyseiina N. subtribe. Internat. J. Acarol., vol.30, Nr. 3, p. 171-228.

Chmielewski, W., 1971 (a), Wyniki badan morfologicznych, biologicznych iekologicznych nad roztoczkiem suszowym, Carpoglyphus lactis (L.) (Theresults of investigations on the morphology, biology and ecology of thedried-fruit mite, Carpoglyphus lactis (L.)),Prace-Naukowe-Instytutu-Ochrony-Roslin. 1971, publ. 1972, 13: 1, 87-106.

De Moraes, G. J., McMurtry, J. A., Denmark, H. A. & Campos, C. B., 2004.A revised catalog of the mite family Phytoseiidae. Magnolia PressAuckland New Zealand 494 pp.

Chmielewski, W., 1971 (b), Morfologia, biologia i ekologia Carpoglyphuslactis (L., 1758) (Glycyphagidae, Acarina) (The morphology, biology andecology of Carpoglyphus lactis (L., 1758) (Glycyphagidae, Acarina)),Prace-Naukowe-Instytutu-Ochrony-Roslin. 1971, publ. 1972, 13: 2, 63-166.

Hansen, L. S. and Gevti. J., 1985, Possibilities and limitation of theuse of Amblyseius McKenziei Sch. & Pr. for biological control of thrips(Thrips tabaci Lind.) On glasshouse corps of cucumber, Department ofZoology, Danish Research Centre for Plant Protection, Lyngby, Denmark,pp 145-150.

Hughes, A. M., 1977, The mites of stored food and houses. Ministry ofAgriculture, Fisheries and Food, Technical Bulletin No. 9: 400 pp

Hussey, N. W. and N. E. A. Scopes, 1985, Biological Pest Control: theGlasshouse Experience. Poole, UK.: Blandford Press (Ithaca, N.Y.:Cornell University Press)

Jacobson, R. J., 1995, Integrated pest management incucumbers—prevention of establishment of Frankliniella occidentalis(Pergande), Med. Fac. Landbouww. Univ. Gent, 60/3a, pp 857-863.

Karg et al., 1987, Advantages of oligophagous predatory mites forbiological control, Institute of Plant Protection Klenmachnow, pp 66-73.

Karg et al., 1989, Fortschritte bei der Anwendung von Raubmilben zurbiologischen Schädlingsbekämpfung in Gewächshäusern, Gartenbau, 36, pp44-46.

Karg. W., 1989, Die ökologische Differenzierung der Faubmilbarten derÜberfamilie Phytoseiidea KARG (Acarina, Parasitiformes), Zool. Jb. Syst.116, pp 31-46.

Messelink, G. & Steenpaal, S. 2003, Nieuwe roofmijten tegen trips inkomkommer. Groenten & Fruit 43: 34-35.

Messelink, G. 2004, Nieuwe roofmijt wint met overmacht in komkommer.Groenten & Fruit 35: 22-23.

Messelink, G. & Pijnakker, J. 2004, Roofmijten bestrijden wittevlieg.Vakblad voor de Bloemisterij 43: 62.

Messelink, G. & Steenpaal, S. 2004, Roofmijt nu ook kaswittevlieg debaas. Groenten & Fruit 45: 26-27.

McMurtry, J. A. and Croft B. A., 1997, Life-styles of phytoseiid mitesand their role in biological control, Annual Review of Entomology, Vol.42: 291-321.

Nomikou, M., Janssen, A., Schraag, R. and Sabelis, M. W., 2001,Phytoseiid predators as biological control agents for Bemisia tabaci.Exp. Appl. Acarol. 25: 270-290

Parkinson, C. L., 1992, “Culturing free-living astigmatid mites.”Arachnida: Proceedings of a one day symposium on spiders and theirallies held on Saturday 21 Nov. 1987 at the Zoological Society ofLondon, eds. Cooper, J. E., Pearce-Kelly, P, Williams, D. L., p. 62-70.

Ramakers, P. M. J. and Van Lieburg, M. J., 1982, Start of commercialproduction and introduction of Amblyseius mckenzei Sch. & Pr. (Acarina:Phytoseiidae) for the control of Thrips tabaci Lind. (Thysanoptera:Thripidae) in glasshouses, Med. Fac. Landbouww. Rijksuniv. Gent, 47/2,pp 541-545.

Ramakers, P. M. J., 1989, Large scale introductions of Phytoseiidpredators to control thrips on cucumber, Med. Fac. Landbouww. Rijksuniv.Gent, 54/3a, pp 923-929.

Ramakers, P. M. J. and Voet, S. J. P., 1996, Introduction of Amblyseiusdegenerans for thrips control in sweet peppers with potted castor beansas banker plants. IOBC/WPRS working group on integrated control inglasshouses 19 (1): 127-130.

Rasmy et al., 1987, A new diet for reproduction of two predaceous mitesAmblyseius gossipi and Agistemus exsertus (Acari: Phytoseiidae,Stigmaeidae), Entomophaga 32 (3), pp 277-280.

Romeih, A. H. M., El-Saidy, E. M. A. and El Arnaouty, S. A., 2004,Suitability Of Two Lepidopteran Eggs As Alternative Preys For RearingSome Predatory Mites. The first Arab Conference of Applied BiologicalPest Control, Cairo, Egypt, 5-7 Apr. 2004.

Swirski, E., Amitai, S. and Dorzia, N., 1967, Laboratory studies on thefeeding, development and oviposition of the predaceous mite Amblyseiusrubini Swirskii and Amitai an Amblyseius swirskii Athias-Henriot(Acarina: Phytoseiidae) on various kinds of food substances. Israel J.Agric. Res. 17:101-119

Sampson. C., 1998, The commercial development of an Amblyseius cucumeriscontrolled release method for the control of Frankliniella occidentalisin protected crops, The 1998 Brighton conference—Pests & Diseases, 5B-4,pp 409-416.

Solomon, M. E. and Cunnington, A. M., 1963, Rearing acaroid mites,Agricultural Research Council, Pest Infestation Laboratory, Slough,England, pp 399-403.

Teich, Y. 1966, Mites of the family of Phytoseiidae as predators of thetobacco whitefly, Bemisia Ephestia tabaci Gennadius. Israel J. Agric.Res. 16: 141-142.

Wei-Lan Ma and J. E. Laing, 1973, Biology—of Amblyseius (Neoseiulus)californicus, Entomophaga, 47-60.

1. A mite composition comprising: a rearing population of a phytoseiidpredatory mite species, a factitious host population comprising at leastone species selected from the family of the Carpoglyphidae, andoptionally a carrier for individuals of said populations.
 2. Thecomposition according to claim 1, wherein the phytoseiid predatory mitespecies comprises at least one species from the subfamily ofAmblyseiinae or Typhlodrominae.
 3. The composition according to claim 1,comprising a food substance suitable for said factitious hostpopulation.
 4. The composition according to claim 1, wherein thefactitious host population is a rearing population.
 5. The compositionaccording to claim 1, wherein the number of individuals of thephytoseiid predatory mite species relative to the number of individualsof the factitious host is from about 100:1 to 1:20.
 6. A method forrearing a phytoseiid predatory mite comprising: providing a compositionaccording to claim 1, and allowing individuals of said phytoseiidpredatory mite to prey on individuals of said factitious hostpopulation.
 7. A method according to claim 6, wherein the composition ismaintained at least one condition selected from the group consisting of:18-35° C.; and 60-95% relative humidity.
 8. A method according to claim6, wherein said composition comprises a carrier and a suitable foodsubstance and the factitious host population is maintained as athree-dimensional culture on the carrier.
 9. The method according toclaim 6, wherein the phytoseiid mite comprises at least one species fromthe subfamily of Amblyseiinae or Typhlodrominae.
 10. Rearing system forrearing a phytoseiid predatory mite, which system comprises a containerholding the composition according to claim
 1. 11. Rearing systemaccording to claim 10, wherein said container comprises an exit for atleast one mobile life stage of the phytoseiid mite.
 12. Rearing systemaccording to claim 11, wherein said exit is suitable for providing asustained release of said at least one mobile life stage.
 13. A methodfor controlling a pest in a crop, the method comprising: providing acomposition according to claim 1 to said crop.
 14. The method accordingto claim 13 wherein the pest is selected from white flies, thrips,spider mites or tarsonemid mites.
 15. The method according to claim 13,wherein the providing comprises applying an amount of said compositionin the vicinity of said crop.
 16. The method according to claim 15,wherein the amount is from 1-10 ml.
 17. The method according to claim13, wherein the crop is selected from: (greenhouse) vegetable crops;soft fruit; (greenhouse) ornamental crops; or tree crops.
 18. Thecomposition according to claim 1, wherein the factitious host populationcomprises at least one species from the genus Carpoglyphus.
 19. Thecomposition according to claim 1, wherein the factitious host populationcomprises the species Carpoglyphus lactis.
 20. The composition accordingto claim 1, wherein the phytoseiid predatory mite species comprises atleast one species from the genus Amblyseius, Euseius, Neoseiulus,Typhlodromalus, Typhlodromips, Galendromus, or Typhlodromus.
 21. Thecomposition according to claim 1, wherein the phytoseiid predatory mitespecies comprises at least one of Amblyseius andersoni, Amblyseiusswirskii, Amblyseius largoensis, Euseius finlandicus, Euseius hibisci,Euseius ovalis, Euseius victoriensis, Euseius stipulatus, Euseiusscutalis, Euseius tularensis, Euseius addoensis, Euseius citri,Neoseiulus barkeri, Neoseiulus califomicus, Neoseiulus cucumeris,Neoseiulus longispinosus, Neoseiulus womersleyi, Neoseiulus idaeus,Neoseiulus fallacis, Typhlodromalus limonicus, Typhlodromalusperegrinus, Typhlodromips montdorensis, Galendromus occidentalis,Typhlodromus pyri, Typhlodromus doreenae, or Typhlodromus athiasae. 22.The composition according to claim 1, wherein the number of individualsof the phytoseiid predatory mite species relative to the number ofindividuals of the factitious host is from 1:1 to 1:10.
 23. Thecomposition according to claim 1, wherein the number of individuals ofthe phytoseiid predatory mite species relative to the number ofindividuals of the factitious host is 1:4.
 24. The composition accordingto claim 1, wherein the number of individuals of the phytoseiidpredatory mite species relative to the number of individuals of thefactitious host is 1:5.
 25. The composition according to claim 1,wherein the number of individuals of the phytoseiid predatory mitespecies relative to the number of individuals of the factitious host is1:7.
 26. The method according to claim 9, wherein the phytoseiidpredatory mite species comprises at least one species from the genusAmblyseius, Euseius, Neoseiulus, Typhlodromalus, Typhlodromips,Galendromus, or Typhlodromus.
 27. The method according to claim 9,wherein the phytoseiid predatory mite species comprises at least one ofAmblyseius andersoni, Amblyseius swirskii, Amblyseius largoensis,Euseius finlandicus, Euseius hibisci, Euseius ovalis, Euseiusvictoriensis, Euseius stipulatus, Euseius scutalis, Euseius tularensis,Euseius addoensis, Euseius citri , Neoseiulus barkeri, Neoseiuluscalifornicus, Neoseiulus cucumeris, Neoseiulus longispinosus, Neoseiuluswomersleyi, Neoseiulus idaeus, Neoseiulus fallacis, Typhlodromaluslimonicus, Typhlodromalus peregrinus, Typhlodromips montdorensis,Galendromus occidentalis, Typhlodromus pyri, Typhlodromus doreenae, orTyphlodromus athiasae.
 28. The method according to claim 13, wherein thepest is Trialeurodes vaporariorum, Bemisia tabaci, Thrips tabaci,Frankliniella occidentalis, Tetranychus urticae, or Polyphagotarsonemuslatus.
 29. The method according to claim 15, wherein the amount is from2-5 ml.
 30. The method according to claim 13, wherein the crop ispeppers (Capsicum annuum), eggplants (Solanum melogena), Curcubits(Cucurbitaceae), cucumbers (Cucumis sativa), melons (Cucumis melo),watermelons (Citrullus lanatus), strawberries (Fragaria x ananassa),raspberries (Rubus ideaus), roses, gerberas, chrysanthemums, or Citrusspp.